1. Field of the Invention
This invention relates to catalyst compositions of matter comprising ruthenium supported on a surface modified titania support. More particularly, this invention relates to new catalyst compositions, their preparation and use in Fischer-Tropsch hydrocarbon synthesis reactions, said catalyst compositions comprising ruthenium supported on a surface modified titania support, wherein said support comprises a surface modifying oxide of tantalum, vanadium, niobium or mixture thereof in non-crystalline form supported on the surface of said titania.
2. Background of the Disclosure
The use of catalysts comprising one or more catalytic metals supported on a titania or titania-containing support is known in the art. Thus, U.S. Patents 4,042,614; 4,042,615 and 4,116,994 to Vannice and Garten disclose ruthenium, nickel and rhodium, respectively, supported on titania and titania-containing supports as Fischer-Tropsch catalysts for producing hydrocarbons from mixtures of CO and H.sub.2. Ko and Garten in Ethane Hydrogenolysis Studies of TiO.sub.2 -Supported Group VIII Metal Catalysts, J. Catalysis, v. 68, p. 233-236 (1981) disclose each and every one of the Group VIII metals on both silica and titania supports as ethane hydrogenolysis catalysts. Vannice, in a 1982 article titled Titania-Supported Metals as CO Hydrogenation Catalysts, J. Catalysis v. 74, p. 119-202 (1982), discloses each one of the Group VIII metals, except osmium, supported on a titania support for Fischer-Tropsch synthesis of hydrocarbons. In this article, Vannice stated that rhodium and ruthenium on titania did not have as high a CO conversion activity as nickel on titania, but produced more useful hydrocarbons and less methane make than nickel on titania.
In a 1982 article by Wells et al. titled "Support Effects in the Ruthenium Catalyzed Hydrogenation of Carbon Monoxide", appearing on pages 247-254 of Metal-Support and Metal-Additive Effects in Catalysis, Imelik, et al (Ed.), Elsevier 1982, Wells et al also disclose ruthenium supported on titania as a Fischer-Tropsch catalyst. Another article on pages 337-348 of the same book by Reymond et al titled "Influence of the Support or of an Additive on the Catalystic Activity in the Hydrocondensation of Carbon Monoxide by Iron Catalysts" compares iron on various support materials as Fischer-Tropsch catalysts.
U.S. Patent 4,171,320 discloses Fischer-Tropsch synthesis using a catalyst comprising ruthenium on a support comprising at least one refractory Group VA metal oxide. Suitable supports are disclosed in this patent as being vanadia, niobia, tantala, and mixtures of these oxides with other well known inorganic refractory oxides such as alumina, silica, etc. Similarly, U.S. 4,477,595 also discloses Fischer-Tropsch catalysts which may be ruthenium supported on various supports which may include physical mixtures of titania with vanadia, niobia, tantala and mixtures thereof. Still further, U.S. 4,149,998 to Tauster et al. discloses Group VIII metals, including ruthenium, on various supports including oxides of titanium, vanadium, niobium, tantalum and mixtures thereof and particularly zirconium titanate and barium titanate.
U.S. 4,149,998 to Tauster et al. relates to heterogeneous catalysts consisting of Group VIII metals, including ruthenium dispersed on oxide carriers selected from the group consisting of Ti, V, Nb, Ta and mixtures thereof and zirconium titanate and BaTiO.sub.3. However, there is no suggestion in this patent that the catalytic metal to be dispersed on a surface modified titania.